Municipality of Mandra-Eidyllia. Covering an overall area of 426,000,000 m2, Mandra is the largest municipality of Western Attica and one of the largest municipalities in Greece. It used to accommodate the seat of the Municipality of Eleusis, which also included Eleusis and Magoula. On April 2, 1914 .
Mandra was promoted to a community and in 1945 (or 1946) to a municipality. Today, Mandra is a modern and dynamically growing municipality with a population of 12,756, according to the 2001 census. Many small and larger industries, where most of the Mandrans work, are to be found within the Municipality of Mandra. Moreover, the town is renowned for its agricultural and livestock products. In the early 21st century, the municipality has placed a high priority on the improvement of life quality with a number of modern infrastructure projects and activities promoting culture, sports, as well as environmental and social policies.
Vilia is located 56 km to the northwest of Athens. Founded in 1835, the municipality is one of the oldest in Greece, whereas Vilia constitutes one of the few remaining traditional villages of Attica. Located at an altitude of about 600 m, it extends almost amphitheatrically along the southern slope of Mount Cithaeron. Vilia includes coastal areas of Porto Germeno, Psatha, and Alepochori. Its current population has been estimated to include 3,413 inhabitants. Vilia was first inhabited during the Late Byzantine period; in the late 14th century, the village was settled by Arvanites, who were integrated with the locals. The people of Vilia were involved in forestry and animal husbandry occupations, utilising the dense pine forests that covered the area until the German Occupation period. Today, the main occupations of the inhabitants include tourism, agriculture, animal husbandry, beekeeping, fishery, and gum resin collection.
Erythres is located at an altitude of 480 m, on the northern foothills of Mount Cithaeron. The town is located 60 km from Athens, on the borderline separating the prefectures of Attica and Boeotia and, more specifically, along the old Athens-Salonica national road. According to the 1861 census, Erythres had 884 inhabitants and was administered, together with the village of Vilia, by the Municipality of Eidyllia. Although the gradual settlement of farmers from Vilia to Erythres began around 1830-1840, the official detachment of the two municipalities took place in 1875. The population of Erythres was steadily growing since 1879, when an official census counted 1,759 residents. The village boasted 2,566 residents in 1896, 3,120 in 1907, and 3,550 in 1981. The gradual population growth meant an increase in the number of people seeking employment in the surrounding area, particularly in the industrial area of Thebes. According to the 2001 census, Erythres has a population of 3,329. The modern town of Erythres features all modern facilities, while retaining its traditional 19th century architecture.